This is a tip for everyone on the stock rom
There's this app called "LG MLT" that is always running in background and doing some logs.
You can safely disable it from the hidden menu! Here's how:
1. Open the dialer and dial 3845#*605#
2. Scroll down and tap on the MLT
3. Tap on "Enable" to uncheck the box
After you do this you will get more ram available (although you won't be able to see this in the available ram). Your phone will be much faster and there will be less app killing/launcher refreshing.
I just did this and my phone is buttery smooth, just like it was on the first boot (if not even smoother)
Edit: Also remember to use Greenify on all installed apps except apps that have push notifications (Messenger, Viber, etc.), remember to clean your app cache through the settings, clean your internal sdcard.
Edit: Confirmed better multitasking. I had dialer and viber opened and i opened the browser went to the mobile version of howtogeek clicked on a link then tapped the home button. Dialer and viber were still there! Before they would both get killed. (The launcher didn't even refresh!)